This is the 10315th most frequent Russian word.
бросали
"Бросали" means "threw" or "were throwing" in English.
The word 'бросали' here is used to describe the repeated or continuous action of throwing stones into the water.
Дети бросали камни в воду.
The children were throwing stones into the water.
In this case, 'бросали' is employed metaphorically, meaning to abandon or quit, applied to habits.
Они часто бросали свои привычки, начав что-то новое.
They often abandoned their habits when starting something new.
Here, 'бросали' conveys the meaning of leaving or deserting positions.